Epigenetic silencing and other synonymous terms: epi-silenced genes & epimutations. "Genes become aberrantly methylated in tumours through inappropriate activity of methyltransferases. Most common gene inactivation event in tumours. Can be reversed with specific drugs e.g. decitabine" Also: google reveals [www.jci.org/cgi/content/full/105/4/401 Epigenetic gene silencing in cancer Benjamin Tycko]
Li-Fraumeni syndrome reference. Especially section on pathology, perhaps split into aetiology, pathogenicity sequale etc? ;-p